In general, batteries are configured to obtain electric energy by using chemical or physical reaction. Here, chemical batteries are classified into primary and secondary batteries. That is, single-use batteries such as manganese batteries, alkaline batteries, and mercury batteries are called primary batteries, and rechargeable batteries such as rechargeable batteries or lead storage batteries are called secondary batteries.
The secondary batteries are being increasingly expected as power sources for driving motors of vehicles to reduce fossil fuel usage and carbon dioxide (CO2) emission. Such secondary batteries are connected in series or parallel to constitute a battery module so as to increase a voltage or capacity.
However, when the battery module according to the related art is damaged by an external impact, short circuit may occur in the secondary batteries, and high current may flow instantly. Thus, the secondary batteries may be overloaded to cause fire or explosion due to overheating.